1. Field of the Invention
The present invention relates to a liquid jet head which discharges a liquid droplet such as an ink droplet and a method for producing the liquid jet head, particularly to a side-shooter type recording head.
2. Related Background Art
Recently an ink jet recording method spreads rapidly on the point that noise generation in recording is extremely small to an extent that the noise can be neglected, on the point that high-speed recording can be performed, on the point that ink can be fixed onto so-called plain paper, and on the point that the recording can be performed with no particular step. Among ink jet recording heads, the ink jet recording head which discharges a liquid droplet in a perpendicular direction with respect to a substrate, in which an ink discharge energy generating element is formed, is referred to as “side-shooter type recording head.”
As disclosed in U.S. Pat. No. 5,218,376, it is well known that a side-shooter type recording head has a configuration in which the ink liquid droplet is discharged by communicating a bubble, generated by heating a heating resistive element, with outside air. In the side-shooter type recording head, a distance between the ink discharge energy generating element and an orifice (discharge port) can be shortened, the small liquid droplet recording can easily be achieved, and recently required high-resolution recording can be realized.
As shown in FIG. 1, the conventional ink jet recording head frequently has the configuration in which the ink supplied from a side of a cartridge constituting member 110 is supplied onto a heater 116 in a liquid flow path 113 through a supply port 114 formed while piercing through a substrate 111. Usually a passivation layer 119 is formed on an interconnection and an integrated circuit (IC) on a surface in which the substrate 111, the heater 116, and drive circuits thereof are formed. The passivation layer 119 protects the substrate 111, the heater 116, and the drive circuits thereof from oxygen, moisture content, and other chemical damages.
However, a material constituting the substrate 111 is exposed to an inner wall surface of the supply port 114 formed in the substrate 111. Therefore, when the ink has a corrosive property because the ink is not neutral and the like, sometimes the inner wall surface of the substrate 111 is eroded by the ink in association with use of the recording head.
When the material of the substrate 111 is dissolved in the ink, physical properties of the ink, particularly surface tension and viscosity are changed, which has an adverse affect on discharge characteristics of the ink droplet. For example, when the substrate 111 is made of silicon while the ink has alkalinity, the above problem is generated.
The inner wall surface constituting the liquid flow path 113 and an orifice plate 112 in which a discharge port 117 is formed are frequently made of a resin material because the resin material is easily formed. When the orifice plate 112 is made of the resin material, sometimes the orifice plate 112 absorbs the ink to swell in association with the long-term use of the recording head. Particularly, because the orifice plate 112 has a structure in which a region which faces the supply port 114 does not relatively widely abut on the substrate 111, the deformation caused by the swelling is remarkably generated in the region. When the large deformation reaches to a neighborhood of the discharge port 117, a discharge direction of the ink droplet discharged from a nozzle is caused to become unstable, and there is a fear that the orifice plate 112 is peeled off from the substrate 111 due to stress generated by the swelling.